A new labdane diterpene from Vitex negundo

Figures & data

Figure 1.  Structure of negundol (1a + 1b).

Table 1.  ¹H NMR and ¹³C NMR data of negundol (1a + 1b) in CDCl₃

No.	1a		1b
	δH (J in Hz)	δC^a	δH (J in Hz)	δC^a
1a	1.50–1.60 (2H, m)	30.7 t	1.38–1.53 (2H, m)	29.7 t
2a	1.73 (1H, m)	23.6 t	1.73 (1H, m)	23.5 t
2b	1.62 (1H, m)		1.60 (1H, m)
3	4.40 (1H,dd, J = 4.2, 12.0)	81.3 d	4.40 (1H, dd, J = 4.2, 12.0)	80.9 d
4		37.8 s		37.8 s
5	1.54 (1H, m)	46.3 d	1.54 (1H, m)	46.4 d
6a	1.53 (1H, m)	21.0 t	1.52 (1H, m)	21.2 t
6b	1.35 (1H, m)		1.36 (1H, m)
7	1.41 (2H, m)	31.3 t	1.48 (2H, m)	31.2 t
8	1.74 (1H, m)	35.9 d	1.74 (1H, m)	35.9 d
9		94.5 s		95.3 s
10		42.2 s		42.0 s
11a	2.08 (1H, m)	30.0 t	1.80 (2H, m)	29.2 t
11b	1.74 (1H, m)
12a	2.53 (1H, m)	31.2 t	2.12 (1H, m)	36.7 t
12b	1.83 (1H, m)		1.99 (1H, m)
13		88.9 s		86.1 s
14a	2.88 (1H, d, J = 17.4)	42.4 t	3.09 (1H, d, J = 16.8)	39.4 t
14b	2.71 (1H, d, J = 17.4)		2.42 (1H, d, J = 16.8)
15		174.1 s		174.0 s
16	5.87 (1H, s)	103.2 d	5.37 (1H, s)	101.6 d
17	0.82 (3H, d, J = 6.0)	17.6 q	0.82 (3H, d, J = 6.0)	17.5 q
18	0.86 (3H, s)	27.9 q	0.88 (3H, s)	27.8 q
19	0.86 (3H, s)	16.5 q	0.86 (3H, s)	16.5 q
20	0.91 (3H, s)	17.7 q	0.93 (3H, s)	17.1 q
1′		171.7		171.4 s
2′	2.06 (3H, s)	21.4 q	2.05 (3H, s)	21.3 q

^aMultiplicity was determined by DEPT experiments (s = quaternary, d = methine, t = methylene, q = methyl).

Figure 2.  Well-resolved ¹H NMR resonances of negundol (1a + 1b).

Figure 3.  Key HMBC (→) and ¹H-¹H COSY (—) correlations of negundol (1a + 1b).

Table 2.  Antifungal activity of negundol [MIC₈₀ (μg/mL)].

Test organisms	negundol	AMB^a
Candida albicans	64	2
Cryptococcus neoformans	16	2
Trichophyton rubrum	32	16
Aspergillus fumigatus	>128	4

^aAmphotericin B as positive control.